This invention is related to a method and apparatus for analysis of rock samples, and more particularly, core obtained during the drilling of a wellbore through subterranean strata, with an X-ray video fluoroscope.
In the exploration for and production of minerals and hydrocarbons from the earth's surface and subsurface, it is common practice to obtain rock samples from the subterranean strata or formations of interest. These rock samples are usually obtained from outcroppings of the subterranean strata or from wellbores drilled through the overlaying strata to the subterranean strata of interest. These rock samples are normally analyzed through visual inspection for internal features, such as bedding laminations, fractures, and localized mineralization. However, this type of analysis often requires that the rock sample be cut up, thus resulting in destruction of the particular rock sample.
More particularly, in the drilling of wellbores for the exploration for and production of hydrocarbons from subsurface formations, it is common practice to obtain rock samples in the form of core cut through some of the subterranean formations through which the wellbore is drilled. This core is cut and retrieved in sections of varying length. This core is normally analyzed, through visual petrologic and sedimentologic evaluations and determinations of bedding laminations, fractures and localized mineralization, to provide important information related to depositional environment, structural history, or diagenetic processes. However, since these types of geological evaluations commonly require that the core be slabbed, such evaluations have either been delayed in the past until after production testing, such as fluid flow studies in sections of the core, or core analysis, requiring whole core have been completed, or have not been performed, in cases where there is a need to keep the core sealed or where production testing or core analysis has virtually destroyed the core.
Accordingly, there is a need for a method of and apparatus for nondestructive analysis of rock samples and, more particularly, core obtained during the drilling of a wellbore through subterranean strata to determine the presence of and evaluate such internal features as bedding, laminations, fractures, and localized mineralization.